The receipt of unsolicited and unwanted facsimile transmissions (sometimes referred to as “spam” or “junk” transmissions) is an increasing problem. Spam transmissions are typically sent to a plurality of recipients by an automated machine that automatically dials a plurality of fax numbers, usually in sequence. Should the machine encounter a line that is busy, unanswered or otherwise unavailable, it abandons that particular call and moves on to the next fax number. The abandoned call is typically tried again at a later time.